Java 实现验证码

将验证码放到session中
    try {
            //设置长宽
            VerifyCodeGenUtils verifyCodeGenUtils = new VerifyCodeGenUtils();
            VerifyCode verifyCode = verifyCodeGenUtils.generate(80, 36);
            String code = verifyCode.getCode();
            // 方式一：（session）将VerifyCode绑定session
             request.getSession().setAttribute("verifyCode", code);

            // 待提交登录时候获取服务器存储的验证码作为比较
            // String verifyCode1 = (String) request.getSession().getAttribute("VerifyCode");

            // 方式二：（redis）获取session id 作为key,时间存5分钟
           // redisUtils.set("VerifyCode_" + request.getSession().getId(), code, 300);

            //设置响应头
            response.setHeader("Pragma", "no-cache");
            //设置响应头
            response.setHeader("Cache-Control", "no-cache");
            //在代理服务器端防止缓冲
            response.setDateHeader("Expires", 0);
            //设置响应内容类型
            response.setContentType("image/jpeg");
            response.getOutputStream().write(verifyCode.getImgBytes());
            response.getOutputStream().flush();
        } catch (IOException e) {

        }

import com.suncere.air.diagnosis.bus.entity.VerifyCode;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Service;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;
public class VerifyCodeGenUtils {

    private static final Logger logger = LoggerFactory.getLogger(VerifyCodeGenUtils.class);

    private static final String[] FONT_TYPES = {"u5b8bu4f53", "u65b0u5b8bu4f53", "u9ed1u4f53", "u6977u4f53", "u96b6u4e66"};

    private static final int VALICATE_CODE_LENGTH = 4;

    
    private static void fillBackground(Graphics graphics, int width, int height) {
        // 填充背景
        graphics.setColor(Color.WHITE);
        //设置矩形坐标x y 为0
        graphics.fillRect(0, 0, width, height);

        // 加入干扰线条
        for (int i = 0; i < 8; i++) {
            //设置随机颜色算法参数
            graphics.setColor(VerifyCodeRandomUtils.randomColor(40, 150));
            Random random = new Random();
            int x = random.nextInt(width);
            int y = random.nextInt(height);
            int x1 = random.nextInt(width);
            int y1 = random.nextInt(height);
            graphics.drawLine(x, y, x1, y1);
        }
    }

    
    public String generate(int width, int height, OutputStream os) throws IOException {
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics graphics = image.getGraphics();
        fillBackground(graphics, width, height);
        String randomStr = VerifyCodeRandomUtils.randomString(VALICATE_CODE_LENGTH);
        createCharacter(graphics, randomStr);
        graphics.dispose();
        //设置JPEG格式
        ImageIO.write(image, "JPEG", os);
        return randomStr;
    }

    
    public VerifyCode generate(int width, int height) {
        VerifyCode verifyCode = null;
        try (
                //将流的初始化放到这里就不需要手动关闭流
                ByteArrayOutputStream baos = new ByteArrayOutputStream();
        ) {
            String code = generate(width, height, baos);
            verifyCode = new VerifyCode();
            verifyCode.setCode(code);
            verifyCode.setImgBytes(baos.toByteArray());
        } catch (IOException e) {
            logger.error(e.getMessage(), e);
            verifyCode = null;
        }
        return verifyCode;
    }

    
    private void createCharacter(Graphics g, String randomStr) {
        char[] charArray = randomStr.toCharArray();
        for (int i = 0; i < charArray.length; i++) {
            //设置RGB颜色算法参数
            g.setColor(new Color(50 + VerifyCodeRandomUtils.nextInt(100),
                    50 + VerifyCodeRandomUtils.nextInt(100), 50 + VerifyCodeRandomUtils.nextInt(100)));
            //设置字体大小，类型
            g.setFont(new Font(FONT_TYPES[VerifyCodeRandomUtils.nextInt(FONT_TYPES.length)], Font.BOLD, 26));
            //设置x y 坐标
            g.drawString(String.valueOf(charArray[i]), 15 * i + 5, 19 + VerifyCodeRandomUtils.nextInt(8));
        }
    }
}

import org.apache.commons.lang3.RandomUtils;
import java.awt.Color;
import java.util.Random;
public class VerifyCodeRandomUtils extends RandomUtils {
    private static final char[] CODE_SEQ = {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J',
            'K', 'L', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W',
            'X', 'Y', 'Z', '2', '3', '4', '5', '6', '7', '8', '9'};

    private static final char[] NUMBER_ARRAY = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9'};

    private static Random random = new Random();

    public static String randomString(int length) {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < length; i++) {
            sb.append(String.valueOf(CODE_SEQ[random.nextInt(CODE_SEQ.length)]));
        }
        return sb.toString();
    }

    public static String randomNumberString(int length) {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < length; i++) {
            sb.append(String.valueOf(NUMBER_ARRAY[random.nextInt(NUMBER_ARRAY.length)]));
        }
        return sb.toString();
    }

    public static Color randomColor(int fc, int bc) {
        int f = fc;
        int b = bc;
        Random random = new Random();
        if (f > 255) {
            f = 255;
        }
        if (b > 255) {
            b = 255;
        }
        return new Color(f + random.nextInt(b - f), f + random.nextInt(b - f), f + random.nextInt(b - f));
    }

    public static int nextInt(int bound) {
        return random.nextInt(bound);
    }
}

 String sessionVerifyCode = (String) request.getSession().getAttribute("verifyCode");